package com.baba.vote.util;

/**
 * @author moxinHuoHuo
 * @create 2019/10/29 下午5:26
 */
public class Locationutil {

  private static double EARTH_RADIUS = 6378.137;

  private static double rad(double d) {
    return d * Math.PI / 180.0;
  }

  /**
   * 通过经纬度获取距离(单位：米)
   * @param lat1 A点纬度
   * @param lng1 A点经度
   * @param lat2 B点纬度
   * @param lng2 B点经度
   * @return 距离     
   */
  public static double getDistance(double lat1, double lng1, double lat2, double lng2) {
    double radLat1 = rad(lat1);
    double radLat2 = rad(lat2);
    double a = radLat1 - radLat2;
    double b = rad(lng1) - rad(lng2);
    double s = 2 * Math.asin(Math.sqrt(Math.pow(Math.sin(a / 2), 2) + Math.cos(radLat1) * Math.cos(radLat2) * Math.pow(Math.sin(b / 2), 2)));
    s = s * EARTH_RADIUS;
    s = Math.round(s * 10000d) / 10000d;
    s = s * 1000;
    return s;
  }

}
